The present invention relates to in-flight entertainment (IFE) systems and specifically to a cellular wireless network for aircraft passenger cabins.
In-flight entertainment systems have been installed on commercial airliners for a number of years. An in-flight entertainment system typically comprises the components necessary to present entertainment content to an airline passenger while in flight. Current IFE systems are wired systems that deliver programming to passengers similar to a cable television system. The current systems comprise head end equipment where programming and control functions originate, a distribution subsystem and display systems. The entertainment content is distributed from the head end equipment to passengers by means of the distribution system. The display system receives the content from the distribution system, processes the content and displays it to the airline passengers.
Current IFE systems are best installed as an aircraft is being built. Existing aircraft may have retrofit systems installed. However retrofitting an existing aircraft with new wiring and cables is difficult and expensive. In addition wired systems are heavy due to the amount of wiring required to connect all the seats in an aircraft, comprise a large number of line replaceable units (LRU) such as distribution box equipment and seat equipment, and consume large amounts of power due to the large number of LRUs. Having a large number of LRUs also reduces reliability and increases cost.
Wireless IFE distribution systems offer many advantages over wired systems in an aircraft cabin. Retrofit installations on existing aircraft are much easier to accomplish due to the elimination of wires and cables. Finding locations for the many LRUs such as seat equipment is not required in a wireless system. Weight and power reductions are easily achievable with a wireless distribution system. Fewer LRUs result in less maintenance, more flexibility in IFE system installations, increased reliability, and reduced costs.
Aircraft cabins offer a considerable design challenge when developing a wireless distribution system for an IFE system. Standard wireless RF networking in an aircraft cabin can be suboptimal due to uneven coverage. Due to very complex aircraft absorption and blockage factors a single antenna for the whole cabin has been found to be not practical. The aircraft cabin's unique half-section linear tube shape (longer than it is wide by a factor of 5:1 in some cases) requires a beam pattern from an antenna system that does not overemphasize lateral RF projection otherwise self interference of repeating bands used within the system may occur.
An IFE system can require megabits of individual channel capacity in order to maintain video and other data services. Commercial off-the-shelf (COTS) wireless local area network (LAN) access point systems used to serve personal electronic devices however are relatively band limited when considered to serve hundreds of passengers. COTS systems do not provide enough aggregate bandwidth to enable an entire cabin of hundreds of passengers each with their own unique bandwidth requirements.
A multiple antenna cellular network can be used with beam shaping to compensate for cabin geometry as well as for adjacent cell interference potential. Each multiband cell antenna within each physical access point as a system must be controllable to maximally cover multi-seat cell areas. Due to bandwidth limitations, RF bands must be reused to enable coverage within a large aircraft cabin. Since a cellular LAN system is wireless, passenger registration is uncertain and the system must therefore be able to register and locate passenger wireless seat displays. Registration or log in is needed to send protocols and data unique to each passenger wireless seat display. The cellular network must be scalable to fit most cabin configurations and passenger wireless needs and requires network load balancing to prevent poor video or audio quality due to overloading in a cell. Therefore a cabin cellular wireless system having a wireless network server system and a wireless access point and configurable antenna system meeting IFE requirements is needed.